Incorrect use of logging module causing poor performance

[jamescasbon]

This code is in engine...

    logger.debug('setting nodelevel(%s) input %s = %s' % (str(self),
                                                          parameter,
                                                          str(val)))

The str calls here are not needed. The logger should call str if needed. By doing this, you pay the cost of string representing inputs even when debug logging is not activated. For very large objects, this can be significant.

[oesteban]

Indeed, we should specify parameters as logger arguments instead of using formatting (http://docs.pylint.org/features.html, W1201)